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Message-ID: <20150806170108.GA21052@openwall.com>
Date: Thu, 6 Aug 2015 20:01:09 +0300
From: Solar Designer <solar@...nwall.com>
To: john-dev@...ts.openwall.com
Subject: Re: auditing our use of FMT_* flags
Kai,
On Mon, Jul 27, 2015 at 11:24:21AM +0200, magnum wrote:
> On 2015-07-27 09:48, Kai Zhao wrote:
> >$ ./john --test=0 --format=LM
> >Will run 8 OpenMP threads
> >Testing: LM [DES 256/256 AVX2-16]... (8xOMP) PASS
> >
> >Change the first password: "AAAAAA" -> "AAAAAa"
> >
> >$ ./john --test=0 --format=LM
> >Will run 8 OpenMP threads
> >Testing: LM [DES 256/256 AVX2-16]... (8xOMP) FAILED (get_key(0))
>
> The format DOES change the case to upper but since the test vector still
> has it in lower, it fails. This is just a current technical aspect of
> self-tests, you can ignore it.
As magnum correctly pointed out, your test is sort of wrong. It detects
that get_key() isn't returning the key that was previously set. For LM,
that's deliberate: the key is visibly converted to uppercase, and we
want it written to john.pot that way. In order not to trigger this
detection on our normal self-test, we provide all of the test vectors
with already all-uppercase passwords. There's certainly room for
improvement here: to be able to self-test the uppercasing and truncation
at length 7, yet check that get_key() returns mostly the same password,
modulo case and truncation (check for the flags and max length first).
An improvement like that would apply to our old, quick self-test as
well. Then we'd be able to list test vectors that would be meant to be
uppercased and truncated.
As to your --test-full also detecting this non-issue, this appears to be
due to the get_key() check included in is_key_right() even when called
from test_fmt_case(), test_fmt_8_bit(), and fmt_self_test_full_body().
You need to either have the get_key() check skipped when invoked from
there, or enhance it as I have described above.
Alexander
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